KR20070013321A - Method of improving soft ground - Google Patents

Abstract

[PROBLEMS] A method of improving soft ground, capable of effectively restricting settlement of a peripheral part of ground to be improved involved in improvement of the soft ground. [MEANS FOR SOLVING PROBLEMS] A vertical supply path is formed by placing a vertical drain material (101) in ground (B) in the periphery of ground to be improved, and water containing a water stop material (102) is charged in the vertical supply path to supply the water containing the water stop material (102) to the ground (B) through the vertical supply path. Then the water stop material (102) charged in the vertical supply path follows a water flow and spreads in the periphery of the vertical supply path to form a water stop zone (107). The water stop zone (107) formed by the water stop material (102) prevents the movement of ground water in the ground (B) and restricts lowering of the ground water in the ground (B) caused by forced drainage from ground (A) to be improved, effectively restricting settlement of the ground (B) involved in improvement of soft ground. ® KIPO & WIPO 2007

Description

Method of improving soft ground

TECHNICAL FIELD This invention relates to the improvement method of the soft ground suitable for soft ground, for example, the landfill composition area | regions around a lake and a swamp. In detail, the present invention relates to a method for improving a soft ground, which can effectively suppress a decrease in groundwater at the periphery of an improved ground caused by an improved soft ground.

Conventionally, as an improved construction method of a soft ground, the upper surface of a soft ground (hereinafter referred to as an improved ground) to be improved is covered with an airtight sheet, a vacuum pressure is applied to the improved ground, and a reduced pressure region isolated from the surrounding ground of the improved ground is separated. At the same time, the soft ground is improved to a hard ground by laying it on the soft ground and applying a consolidation load of the fill.

Specifically, as shown in FIG. 17, the vertical drain material 1 is poured in the improved ground A at predetermined intervals, and then contacted with the upper end portion 1a of each of the vertical drain material 1. The horizontal drain 2 is arrange | positioned, Then, the collection pipe 3 connected to the vacuum pump 5 via the vacuum duct 4 is connected to this horizontal drain material 2, and the upper surface of the improved ground A is further connected. The upper end portion 1a of the vertical drain material 1, the horizontal drain material 2, and the collecting pipe 3 are covered with an airtight sheet 7. Thereafter, the vacuum pump 5 connected to the water collecting pipe 3 through the vacuum duct 4 is operated.

As a result, the vacuum pressure from the vacuum pump 5 propagates to the improved ground A through the horizontal drain material 2 and the vertical drain material 1, and the ground around the vertical drain material 1 around it. To be a region in a reduced pressure state (hereinafter referred to as a reduced pressure region).

The vacuum pressure propagates from the ground around the vertical drain material 1, which has become a reduced pressure region, to the ground around the outer side, and as a result, ground pressurization (water pressure, earth pressure) directed to the vertical drain 1 occurs.

By this ground pressurization, the gap water contained in the ground around the vertical drain material 1 is sucked toward the vertical drain material 1, and the vertical drain material 1, the horizontal drain material 2, and the water collecting pipe 3 are Is discharged as a drainage path, and thus the ground around the outer side of the ground around the vertical drain material 1 also becomes a decompression region.

In this way, the pressure reduction area | region becomes wider to the ground around the vertical drain material 1, and the whole improvement ground A becomes a pressure reduction area | region, and consolidation centering on the vertical drain material 1 at the same time, Increasing strength progresses, consolidation and improvement of strength throughout the improved ground A are performed.

As described above, the improvement is made to the hard ground, and as the fill 6 is placed on the airtight sheet 7, consolidation and dehydration of the improved ground A is performed by the consolidation load of the fill 6. By the suction and the joint action by the pressure difference, consolidation settlement of the improved ground A is promoted (Japanese Patent No. 3270968 Publication (claims 1 and 2, see FIG. 7)).

[Initiation of invention]

[Problem to Solve Invention]

However, in the above-mentioned forced consolidation dehydration method, although the groundwater of the improved ground is forcibly drained by vacuum pressure, when a sand layer or an organic soil layer having high permeability exists in the ground over the improved ground and the surrounding ground, FIG. 17. As indicated by the arrow, the groundwater of the improved ground periphery B is also forcibly drained, so that the groundwater of the improved ground periphery also decreases, and this influence promotes self-consolidation of the soft surrounding ground and settles down.

In the case of settlement caused by drainage of groundwater, the influence range extends with time, and it is adversely affected by the forced consolidation dehydration method that requires sufficient consolidation time to maintain the quality of the ground improvement. It is necessary to take measures to make as small as possible.

This invention is made | formed in view of such a technical subject, and an object of this invention is to provide the improvement method of the soft ground which can suppress the fall of the groundwater of the improved ground periphery by the improvement of the soft ground effectively.

[Means for solving the problem]

In order to achieve the above object, the invention described in claims 1 to 14 uses a vacuum pressure in the improved ground to create a reduced pressure area isolated from the improved ground periphery, and drains the gap water in the improved ground, thereby making the improved ground hard. In the improved construction method of the soft ground (hereinafter simply referred to as an improved construction method) to be improved, a vertical feed passage is formed in the ground of the improved ground and / or the periphery of the improved ground, and an index material is formed in the vertical feed passage. The improved construction method characterized by supplying the water containing the index material into the improved ground and / or the ground around the improved ground through the said vertical supply path was made into the summary.

According to the invention described in Claims 15 to 30, in the improved construction method, a vertical supply passage is formed in the ground around the improved ground, and water is injected into the vertical supply passage together with water, and the vertical supply passage and the improved ground An improved construction method is provided by forming a vertical drainage channel between the outside of the vertical supply path and / or draining water in the ground around the improved ground periphery through the vertical drainage path.

[Effects of the Invention]

In the improved construction method according to claims 1 to 14, a vertical supply path is formed in the ground of the improved ground and / or the improved ground periphery, and the index material is included in the ground of the improved ground and / or the improved ground periphery through the vertical supply passage. Since the water is supplied, the index material introduced into the vertical feed passage diffuses around the vertical feed passage along the flow of water to form an index zone.

The exponential zone formed by the water repellent material can inhibit the movement of groundwater in the ground around the improved ground and / or the improved ground, and can suppress the decrease of groundwater in the ground around the improved ground due to the forced drainage of the groundwater of the improved ground, It is possible to effectively suppress the ground subsidence of the improved ground periphery due to the ground improvement.

In the improved construction method according to claim 15 to 30, water is introduced into the vertical supply passage formed in the surrounding ground together with water, while the vertical supply passage and the improved ground and / or the outside of the vertical supply passage are vertical. Since a drainage channel was formed and the water in the ground of the improved ground periphery was drained through the vertical drainage, the index material introduced into the vertical supply passage diffuses in accordance with the flow of water from the vertical supply passage to the vertical drainage channel, and in the ground around the improved ground periphery. Form an exponential zone.

The index zone formed by the water retardant inhibits the movement of groundwater in the ground at the periphery of the improved ground, and can suppress the decrease of the groundwater in the ground at the periphery of the improved ground due to the forced drainage of the ground water of the improved ground. The ground subsidence of the improved ground periphery can be effectively suppressed.

In this improvement method, since the index material spreads on the water flow from the vertical supply path to the vertical drainage, the index zone is smoothly and reliably formed, and the settlement effect of the ground around the improved ground periphery due to the improvement of the soft ground can be expected at an early stage. Can be.

1 is a schematic cross-sectional view showing an application example of the improved construction method of the present invention.

2 is a schematic cross-sectional view showing a vertical supply path.

3 is a schematic plan view showing a vertical supply passage in the same manner.

4 is a schematic diagram showing an input system of water containing an index component.

5 is an enlarged perspective view of a main portion showing an example in which a sand layer is provided around an upper end portion of a vertical drain material poured in the improved ground and / or the surrounding ground;

6 is a schematic sectional view showing another example of the vertical feed passage.

7 is a schematic cross-sectional view showing an application example of the improved construction method of the present invention.

8 is a schematic plan view of FIG. 7 in the same manner.

Fig. 9 is a schematic cross-sectional view showing the flow of water and a still water produced by operating a vacuum pump while simultaneously introducing a still water with water into the vertical drain;

10 is a schematic plan view of FIG. 9 in the same manner.

11 is a schematic cross-sectional view showing an index zone formed between an improved ground and a surrounding ground by the improved construction method of the present invention.

12 is a schematic plan view of FIG. 11 in the same manner.

FIG. 13 is a cross-sectional schematic diagram showing another application example of the improved construction method of the present invention, wherein the water and the water flow produced by operating the vacuum pump while simultaneously adding the water flow material with the water in the vertical drain; FIG.

14 is a cross-sectional schematic diagram showing an index zone formed in a surrounding ground by the improved construction method shown in FIG. 13.

FIG. 15 is a cross-sectional schematic diagram showing another application example of the improved construction method of the present invention, wherein the water and the water flow produced by operating the vacuum pump while simultaneously inserting the water flow with the water in the vertical drain. FIG.

16 is a cross-sectional schematic diagram illustrating an index zone formed in a surrounding ground by the improved construction method shown in FIG. 15.

17 is a schematic diagram showing an application example of a conventional improved construction method.

<Explanation of symbols for the main parts of the drawings>

11, 101, 103, 103a, 103b: vertical drain material

12, 104, 104a, 104b: horizontal drain material

13, 106, 106a, 106b: airtight sheet

15, 105, 105a, 105b: vacuum pump

102: Index material

107, 107a, 107b: Index Zone

108: Index Tank

109: feed pump

109a: return pipe

110: float check valve

111: layer of gravel or coarse sand

112: frame

113: input pipe

115: home

 A: Improved ground

 B: surrounding ground

 C: High permeability sand layer or organic soil layer

 D: middle gravel layer

Best Mode for Carrying Out the Invention

EMBODIMENT OF THE INVENTION Hereinafter, the improvement method of this invention is demonstrated in detail according to one Embodiment shown in drawing. The improved construction method of Claims 1-14 is demonstrated. This improved construction method uses a vacuum pressure to create a reduced pressure area isolated from the improved ground periphery and drains the gap water in the soft ground, thereby improving the soft ground to hard ground.

There is no particular limitation on the method of creating a reduced pressure region isolated from the surrounding area of the improved ground using vacuum pressure in the ground. For example, the improved method described in Japanese Patent No. 3270968 and Japanese Unexamined Patent Publication No. 2003-55951 proposed by the present inventor is more efficient than the conventional method using a conventional sand mat. It is preferable at the point that pneumatic pressure can be added in improved ground and more effective improvement can be implement | achieved.

The improved method described in Japanese Patent No. 3270968 is a method of covering the upper surface of the improved ground with an airtight sheet and applying a vacuum pressure to the improved ground, thereby creating a reduced pressure region isolated from the surrounding ground of the improved ground, As shown in FIG. 1, the process of forming a vertical drain wall in the ground A by pouring the vertical drain material 11 at predetermined intervals leaving the upper end part in the improved ground A, and a vacuum pump P ) Is arranged in a horizontal shape so as to contact the vertical drain upper end portion 11a, and the airtight sheet together with the vertical drain material upper end portion 11a and the horizontal drain material 12 on the ground A. (13) and the vacuum pump 15 connected through the horizontal drain 12, the collection pipe 14 and the vacuum tank (not shown) to operate the state of the vacuum pressure on the ground (A) Making ball It is made of.

In addition, as shown in Japanese Laid-Open Patent Publication No. 2003-55951, in the ground improvement, by applying a vacuum pressure to create a reduced pressure region in the improved ground, the gap water sucked out from the improved ground is different from the propagation path of the vacuum pressure. It may be discharged through another drainage path.

Specifically, as shown in FIG. 1, the improvement below the water collecting pipe 14 connected to each of the vertical drain materials 11 provided at predetermined intervals in the improved ground A through the horizontal drain material 12. The drain tank 16 which communicates with the exterior of the improved ground A in the ground A is arrange | positioned, and the clearance water collected by the said collection pipe 14 is drained to the said drain tank 16. FIG.

In this case, as shown in FIG. 1, the collection pipe 14 and the drain tank 16 are connected through the separator 18 which isolate | separates water and air using gravity, and the separator 18 makes the said It is preferable that the gap water in the collection pipe 14 is fed to the drain tank 16. In addition, a drain pump 17 is incorporated in the drain tank 16 to force the gap water in the drain tank 16 to the outside of the improved ground A through a drain pipe 19 connected to the outside of the improved ground A. By draining away, more efficient drainage becomes possible.

In addition, as shown in FIG. 1, in the ground improvement, the fill 20 can be applied on the soft ground A, and a fill load can be applied. The fill 20 is placed on the airtight sheet 13. As a result, the consolidation and dehydration of the improved ground A is performed more efficiently by the consolidation load of the fill soil 20, and the consolidation settlement of the improved ground A is promoted by suction and joint action by the pressure difference. do.

In the above-described improved construction method, a vertical supply passage is formed in an improved ground and / or ground around an improved ground (hereinafter referred to as a peripheral ground), and water containing a water repellent material is introduced into the vertical supply passage. In addition, the vertical supply path is characterized by supplying water including the water repellent material in the improved ground and / or the surrounding ground.

As described above, when consolidation and dehydration of the improved ground A is performed, and consolidation settlement of the improved ground A is promoted by suction and cooperative action of the gap water due to the pressure difference, the improved ground A is shown in FIG. 2. ) And the permeable sand layer or organic soil layer (C) exist between the ground and the surrounding ground (B), the groundwater in the surrounding ground (B) other than the improved ground (A) is also forcibly drained. Therefore, the soft surrounding ground B may also cause settlement or the like due to its influence.

In order to avoid such a situation, in the improved construction method of the present invention, a vertical supply passage is formed in the improved ground and / or the surrounding ground, and water containing the water repellent material is introduced into the vertical supply passage.

Specifically, as shown in FIGS. 1 to 3, a plurality of vertical drain materials 101 are poured into the surrounding ground B at predetermined intervals so as to surround the improved ground A, thereby forming a vertical supply path. In this case, it is preferable to form the vertical supply path slightly away from the improved ground A. Specifically, it is good to be prepared 1 to 2 m away from the improved ground (A).

FIG. 5 shows a form in which a vertical supply path is formed by pouring a plurality of vertical drain materials 101 at predetermined intervals into a boundary portion with the surrounding ground B in the improved ground A. FIG.

Further, the vertical supply path may be formed at predetermined intervals so as to surround the improved ground A in the surrounding ground B depending on the type of the improved ground A or the surrounding ground B, or in the improved ground A. It is not necessary to create at predetermined intervals at the boundary portion with the surrounding ground (B), and in the improved ground (A) or the surrounding ground (B), the groundwater of the surrounding ground (B) is forced to drain according to the ground improvement. It is good to concentrate on the part with concern.

1 to 3 or 5 show an example in which a vertical supply path is formed in the improved ground A or the surrounding ground B, but the types and permeability of the improved ground A and the surrounding ground B are shown. Depending on the scale and shape of the high sand layer or the organic soil layer (C), it is also possible to form a vertical supply path in the improved ground (A) and the surrounding ground (B).

As the vertical drain material 101 to be used, any path that supplies water including the water retardant material in the depth direction of the improved ground A or the surrounding ground B may be used. It is also possible to use a net as a core material, and to provide the filter layer which consists of fibrous sheets, such as a nonwoven fabric, a felt, a woven fabric, and a knit fabric, in the front and back of this net. In this case, it is preferable that the filter layer of the vertical drain material 101 is comprised by the fiber sheet which has the hole of the magnitude | size which can penetrate the index material 102. FIG.

In addition, in addition to placing the vertical drain material 101, the vertical supply path pipes a pipe (hole tube) having a plurality of holes through which the water repellent material 102 can penetrate into the improved ground A or the surrounding ground B in the depth direction. It is also possible to compose by a method.

Examples of the water containing the water reproducing material 102 to be introduced into the vertical supply path (the vertical drain 101 or the pipe with a hole) of the improved ground A and / or the surrounding ground B include, for example, CMC or sodium alginate. It can take the form of suspension of hydrophilic gel which consists of polysaccharide salts, such as the salt which has as a main component.

In the case where water containing such an index material is introduced into the vertical supply path 101, for example, as shown in FIG. 4, an index material for storing water (hydrophilic gel suspension) containing the index material is shown. The water containing the water repellent material may be supplied into the vertical supply path 101 through the supply pipe 109 from the tank 108.

In this case, the hydrophilic gel suspension introduced into the vertical feed passage 101 from the water tank 108 through the supply pipe 109 is flowed down into the vertical feed passage 101 as it is, and the vertical flow is performed according to the force of this water flow. Through the drain 101 (or the pipe with a hole), it flows out to the highly permeable sand layer or the organic soil layer C existing between the improved ground A and the surrounding ground B.

As shown in Figs. 1 to 3, a part of the water repellent material 102 (hydrophilic gel) is suspended in the sand layer or the organic soil layer C in the suspension spread out of the sand layer having high permeability or the organic soil layer C. And a partial blockage phenomenon is produced, and the water flow rate is lowered.

The water containing the water repellent material 102 (hydrophilic gel) concentrates on the interstitial part (part where no blockage has occurred) of the partially permeable sand layer or the organic soil layer C, and speeds up the interstitial part. Pass it up. In the process, the water repellent material 102 (hydrophilic gel) closes the gap portion.

In this way, the interlayer portions in the sand layer or organic soil layer C having high water permeability are sequentially closed by the water reproducing material 102 (hydrophilic gel), and as shown in FIGS. 2, 3 and 5. The index zone 107 made of the water repellent material 102 (hydrophilic gel) is formed by the action of overlapping bonding under pressure in the sand layer or the organic soil layer C having high water permeability.

By this water stop zone 107, the flow path of the groundwater which consists of the highly permeable sand layer and the organic soil layer C between the improved ground A and the surrounding ground B is not interrupted, and it is for forced drainage of the ground improvement. Therefore, the situation that the groundwater of the surrounding ground B falls will be avoided.

On the other hand, when there is no high permeability sand layer or organic soil layer (C) or the intermediate gravel layer (D) exists above the high permeability sand layer or organic soil layer (C) over the improved and surrounding grounds. Even if the water (hydrophilic gel suspension) containing the index member 102 passes through the intermediate gravel layer D, the index member 102 does not stay in the intermediate gravel layer D, and is taken as it is through the improved ground ( A) will move to the side.

The water discharge material 102 (hydrophilic gel) flowing in the middle gravel layer D between the improved ground A and the surrounding ground B toward the improved ground A according to the water flow is a vertical drainage channel formed in the improved ground A. It leads to the vertical drain 11 which comprises. In the form shown in the drawing, the vertical drain material 11 constituted by a filter layer having a hole having a size that does not pass through the water-absorbing material 102 (hydrophilic gel) whose surface is absorbed and expanded is improved by pouring it. A vertical drainage channel is formed in the ground A. Therefore, the water repellent material 102 (hydrophilic gel) which has reached the vertical drain 11 in accordance with the water flow is blocked by the filter layer on the surface of the vertical drain 11, and cannot penetrate into the interior. By sticking to each other and clogging occurs in the filter layer on the surface of the vertical drain 11, whereby the index zone 107 is formed.

The index zone 107 formed in the filter layer on the surface of the vertical drain 11 has a vertical drain material on the side of the improved ground A to improve the flow of groundwater in the intermediate gravel layer D across the improved ground A and the surrounding ground B. 11), the groundwater flow path in the middle gravel layer (D) between the improved ground (A) and the surrounding ground (B) is not broken by this index zone 107, It is possible to avoid the situation that the groundwater of the surrounding ground B due to forced drainage decreases.

In addition, when employing the vertical drain material 11 comprised by the filter layer which has the hole of the magnitude | size which the water supply material 102 does not permeate | transmit, and forming the water | coolant zone 107 in the filter layer on the surface of the vertical drain 11, The water discharge material 102 attaches only to a portion of the surface of the vertical drain 11 cast in the improved ground A that touches the intermediate gravel layer D, and forms the water stop zone 107 here, so that the vertical drain 11 Since the original function of the vertical drain 11 is maintained other than the part which contacts the inner and intermediate gravel layers D, there is no possibility of causing damages such as water impermeability and / or air impermeability.

By forming the water stop zone 107 or the partial clogging phenomenon by the water stop material 102 (hydrophilic gel), water movement is lost and water (hydrophilic gel suspension containing the water stop material supplied up to then) is lost. ) Becomes oversupply.

At this time, the float check valve 101 disposed in the vertical feed passage 101 rises with the rise of the liquid level due to the excess supply of water (hydrophilic gel suspension) containing the water repellent material, and the vertical feed passage 101 is supplied. The sphere (not shown) is closed and the supply of water including the water repellent material into the vertical feed passage 101 is cut off. When the supply of water including the water repellent material is cut off, the water containing the water repellent material (hydrophilic gel suspension) which has been introduced into the vertical feed passage 101 from the water repellent tank 108 through the supply pipe 109 is transferred to the vertical supply passage ( 101 is returned to the still water tank 108 through the return pipe 109a without being introduced into the tank 101.

In addition, in this form, depending on the size of the index material (hydrophilic gel), the partially blocked state and the state of formation of the index zone will vary. Therefore, it is preferable to appropriately control the magnitude of the molecular weight and to adjust the size of the gel by judging the kind of the ground or surrounding ground, the scale of the ground improvement, the amount of groundwater, the magnitude of the pressure during the ground improvement, etc. as a whole. . In addition, in the case of using a hydrophilic gel suspension as water containing a water repellent material, since the water retardant zone of the hydrophilic gel is formed by the action of overlapping bonds due to pressure, the hydrophilic gel is returned to the floating state when the pressure difference disappears. After the ground is improved, the original permeability is restored and it is extremely useful as an index measure that is difficult to have a long-term impact on the groundwater environment.

As the water repellent material 102, grains such as coarse sawdust, wood flour, rice hull, rice, barley, millet, blood, soybean, sorghum, or the pulverized product of the grains, Chaff, starch, clay, or carboxymethylcellulose crosslinked product, crosslinked polyacrylate, starch, clay, cement, acrylonitrile graft polymer, PVA-maleic acid copolymer, acetic acid produced when removing the shell (grain) As a vinyl-acrylate copolymer, 1 type, or 2 or more types of mixtures chosen from the superabsorbent polymer whose absorption ratio is 30-1500 times, etc. can also be used.

The index materials such as coarse sawdust and wood flour may also be swollen prior to addition, and may be supplied to the vertical feed passage 101 as a suspension by the apparatus and method shown in FIG.

About index materials, such as said thick sawdust and wood flour, you may swell after input. The following is the explanation. 6 shows a layer 111 made of gravel or coarse sand around the upper portion of the vertical drain material 101 placed in the improved ground A and / or the surrounding ground B, which is made of gravel or coarse sand. It shows the form which throws in water containing the water | water material 102, such as coarse sawdust and wood flour, in the layer 111. As shown in FIG. In the form shown in FIG. 6, a pipe (with or without holes) or frame 112 having a diameter of 15 to 30 cm and a depth of about 10 to 30 cm is provided around the upper portion of the vertical drain material 101, and the pipe or the frame is provided. After removing the earth and sand in 112, it refills with sand and gravel, and the layer 111 of gravel or coarse sand is provided around the upper part of the vertical drain material 101. Into the gravel or coarse sand layer 111, a plurality of input pipes 113 (does not have to have holes) may be inserted, and water containing the water repellent material 102 is introduced through the input pipes 113. It is.

Accordingly, water including the water repellent material 102 introduced through the input pipe 113 is spread all over the layer 111 made of gravel or coarse sand, and water including the water repellent material 102 at once is vertical drain material. It is to be put into 101. That is, by providing a layer 111 of gravel or coarse sand around the upper portion of the vertical drain material 101, the absorbing portion of the water is formed not only around the upper portion of the vertical drain material 101, but also of a layer of gravel or coarse sand ( 111) Since the whole becomes an absorption portion, the rate of supply of water to the vertical drain material 101 is remarkably improved.

6 shows an example in which a layer 111 made of gravel or coarse sand is provided around the upper portion of the vertical drain material 101 placed in the improved ground A and / or the surrounding ground B, but the improved ground Similarly, a layer of gravel or coarse sand may be provided around the upper end portion of the pipe (porous pipe) having a plurality of holes piped in (A) and / or the surrounding ground (B).

It is also possible to include the water repellent material in the gap water from the improved ground A to make the water containing the water repellent material, and to include water containing the water repellent material in the vertical feed passage. In this case, the upper end of the vertical drain 101 (or pipe), which is a vertical supply path formed in the improved ground A and / or the surrounding ground B, is connected to the drain pipe 19 of the gap water from the improved ground A. The groove 115 (or the pipe) is connected, and the gap water from the improved ground A is supplied to the vertical drain 101 (or the pipe) through the groove 115 (or the pipe). At this time, the water injection material 102 is injected into the groove 115 (or the pipe) through which the gap water is drained through the drain pipe 19.

In addition, although supply of the clearance water into a vertical supply path is natural water supply (drainage) in the example shown in FIG. 1 and FIG. 2, a pressurized tank or a pump is arrange | positioned in the drain pipe 19 and the groove 115 (or piping). It is also possible to forcibly feed (drain) the gap water into the vertical feed passage.

The water including the water repellent material 102 introduced into the vertical supply passage flows into the vertical drain 101 (or the pipe with a hole), which is a vertical supply passage, as shown in FIGS. The force flows out through the vertical drain 101 (or the pipe with holes) into the highly permeable sand layer or the organic soil layer C existing between the improved ground A and the surrounding ground B.

The water supply material 102 is also vertically supplied through the flow of water flowing out from the vertical drain material 101 (or the pipe having a hole) constituting the vertical absorption path into the highly permeable sand layer or the organic soil layer C. It flows down into the vertical drain material 101 (or the pipe with a hole) which comprises a furnace, and it flows out into the sand layer or organic soil layer C with high permeability.

A part of the water repellent material 102 spilled into the highly permeable sand layer or the organic soil layer C is stagnated in the sand layer or the organic soil layer C, and depending on the type of the exponent material 102, it is absorbed and expanded here. ), It creates a partial blockage and the water flow rate decreases.

The water including the water repellent material 102 concentrates on the interstitial part (part that is not clogged) of the sand layer or organic soil layer C, which is partially blocked, and has high velocity, and passes through the interstitial part at high speed. In this process, the gap portion is closed by the index member 102.

In this way, the interlayer portions in the sand layer or the organic soil layer C having high permeability are sequentially closed by the water repellent material 102, and the high permeability as shown in Figs. An index zone 107 made of the index material 102 is formed in the sand layer or the organic soil layer C.

By the water-zone zone 107, the flow path of the groundwater made of the highly permeable sand layer or the organic soil layer C between the improved ground A and the surrounding ground B is not broken, and according to the forced drainage of the ground improvement. It is possible to avoid the situation that the groundwater in the surrounding ground B decreases.

In addition, the index member 102 may adopt a form in which microorganisms are mixed. In the case of using such an index member 102, after the index zone 107 is formed by the index member 102, microorganisms multiply and colonies between the index members 102 constituting the index zone 107. ) And reinforcement of the index zone 107 is achieved.

In addition, the nutrient component of microorganisms can be added to water containing an index material. In this case, a large amount of nutrients are contained in the index zone 107 formed in the ground, and the propagation property of soil microorganisms existing in the ground or the microorganisms mixed in the index member 102 is increased, and the index member 102 It will greatly contribute to colony formation of the liver and reinforcement of the index zone 107.

Next, the improved construction method of Claims 15-30 is demonstrated. In addition, this improved construction method uses the vacuum pressure in the soft ground to create a reduced pressure area isolated from the surrounding ground around the improved ground, and drains the gap water in the soft ground, as in the improved construction described in claims 1 to 9 above. Since it is to improve the ground to hard ground, the description here is omitted. In addition, since it is the same as that of the improvement method of Claims 1-9 mentioned above, the kind of water retardant and the input method of the water reinforcement to the vertical supply path are abbreviate | omitted here.

In the above-described improved construction method, the vertical supply passage is formed in the surrounding ground, water is added to the vertical supply passage, and water containing the water repellent material is added to the vertical supply passage, and between the vertical supply passage and the improved ground and / or the It is characterized by providing a vertical drainage path outside the vertical supply path and draining water in the ground of the improved ground periphery through the vertical drainage path.

As described above, when consolidation and dehydration of the improved ground A is performed, and consolidation settlement of the improved ground is promoted by suction and joint action of the gap water due to the pressure difference, high permeability is improved over the improved ground and the surrounding ground to be improved. If a sandy or organic soil is present, groundwater in the ground surrounding the improved ground is also forced to drain. Therefore, there is a concern that settlement of the soft surrounding ground may be caused by the influence.

In order to avoid such a situation, in the improved construction method of the present invention, a vertical supply path is formed at predetermined intervals in the surrounding ground, and water is injected into the vertical supply path together with water. Specifically, as illustrated in FIGS. 7 to 12, a plurality of vertical drain materials 101 are cast in a broken line at predetermined intervals in the surrounding ground B so as to surround the improved ground A. Create a supply path. As the vertical drain material 101 to be used, any path can be provided as long as it can form a water and water supply material in the depth direction of the surrounding ground B. Specifically, a long plastic net is used as the core material. The filter layer which consists of fibrous sheets, such as a nonwoven fabric, a felt, a woven fabric, and a knit fabric, is provided in the front and back. In this case, it is preferable that the filter layer of the vertical drain material 101 is comprised by the fiber sheet which has the hole of the magnitude | size which can penetrate the index material 102. FIG.

In addition, in addition to the pouring of the vertical drain material 101, the vertical supply passage pipes a pipe (hole tube) having a plurality of holes through which the water repellant penetrates in the peripheral ground B in the depth direction, or has a columnar shape in the peripheral ground B. A sand layer can also be provided and formed.

In addition, the vertical supply path does not necessarily need to be formed at predetermined intervals so as to surround the improved ground A depending on the type of the surrounding ground B, and the groundwater in the surrounding ground B may be forced to drain due to the ground improvement. It can also be concentrated only on the part where there is.

In addition, it is preferable to form the vertical supply path as far as possible from the improved ground A. Specifically, it is good to separate it slightly from the improved ground A, for example, about 1 to 2 m away.

Further, a vertical drainage path is formed between the vertical supply path of the surrounding ground and the improved ground and / or outside the vertical supply path. In the form shown in FIG. 7 and FIG. 8, the plurality of vertical drain materials 103 are cast in a broken line at predetermined intervals between the vertical supply path (vertical drain 101) and the improved ground A. FIG. It is formed by doing.

As long as the vertical drain material 103 to be used can form a drainage path in the depth direction of the surrounding ground B, specifically, a long plastic net is used as a core material, and a nonwoven fabric and felt are placed on the front and back of this net. And the one provided with the filter layer which consists of fiber sheets, such as a textile and a knitted fabric, are mentioned. In this case, it is preferable that the filter layer of the vertical drain material 103 is comprised by the fiber sheet which has the hole of the size where the water supply material 102 cannot permeate or is difficult. In addition, in addition to placing the vertical drain material 103, the vertical drainage pipe may be piped in a depth direction to a pipe (hole tube) having a large number of holes or holes that are difficult to penetrate into the surrounding ground B. A columnar sand layer may be provided and formed in B).

Moreover, the horizontal drain material 104 connected to the vacuum pump 105 is connected to the upper end of the vertical drain material 103 which comprises a vertical drainage path, The upper surface is covered with the airtight sheet 106. As shown in FIG.

9 and 10, by introducing water containing the water repellent material 102 into the vertical drain 101 constituting the vertical supply passage and operating the vacuum pump 105, the water is discharged. As shown by the arrow in FIG. 9 and FIG. 10, after flowing down the inside of the vertical drain 101 which is a vertical supply path, the high permeability sand layer or organic soil layer C which exists in the intermediate | middle layer or lower layer of the surrounding ground B is carried out. And flows out of the ground through the vertical drain material 103 constituting the vertical drainage path formed between the vertical supply path (vertical drain 101) and the improved ground A.

The water repellent material 102 is a ground (B) from the vertical drain material 101 constituting the above-mentioned vertical absorption path through the sand layer or organic earth layer (C) having high permeability and the vertical drain material 103 constituting the vertical drainage path. The vertical drain material which flows down the vertical drain material 101 which comprises a vertical supply path, spread | diffuses the sand layer or organic soil layer C with high permeability, and comprises a vertical drainage path by the flow of the water which reaches the outside of the ( 103).

Part of the water repellent material 102 contained in the water stagnates in the sand layer or organic soil layer C having high permeability, and creates a partial blockage state in the sand layer or organic soil layer C having high permeability. Will be lowered. The water including the water repellent material 102 concentrates on the interlayer portion (the portion where no blockage occurs) of the sand layer or the organic soil layer C having a partially blocked permeability, and passes through the interlayer portion at a high speed. In this process, the index member 102 closes the gap portion.

In this way, the interlayer portions in the sand layer or organic soil layer C having high permeability are sequentially closed by the water repellent material 102, and the sand layer or organic layer having high permeability as shown in Figs. An index zone 107 made of the index member 102 is formed in the soil layer C.

By the index zone 107, the flow path of the groundwater consisting of the highly permeable sand layer or the organic soil layer (C) between the improved ground (A) and the surrounding ground (B) is not broken, and according to the forced drainage of the ground improvement. It is possible to avoid the situation that the groundwater in the surrounding ground B decreases.

On the other hand, when the highly permeable sand layer or the organic soil layer (C) does not exist over the improved ground and the surrounding ground, or when the intermediate gravel layer (D) exists above the highly permeable sand layer or the organic soil layer (C), Even if the water including the index material 102 passes through the intermediate gravel layer D, the index material 102 does not stay in the intermediate gravel layer D, and vertical drain material constituting the vertical drainage path as it is by flowing water. It is moved to (103).

The water repellent material 102 that has moved in the intermediate pebble layer D along the water flow in the intermediate pebble layer D is a filter layer having a hole having a size that the water repellent material 102 on the surface of the vertical drain material 103 cannot penetrate or difficult to pass through. Is prevented from entering the vertical drain material 103, adheres to the surface of the vertical drain 11, and causes clogging in the filter layer on the surface of the vertical drain 11, whereby an index zone 107 is formed. do.

The index zone 107 formed in the filter layer on the surface of the vertical drain 103 has a flow rate of groundwater in the intermediate gravel layer D across the improved ground A and the surrounding ground B. 103), and by this index zone 107, the flow path of groundwater in the intermediate gravel layer D between the improved ground A and the surrounding ground B is cut off, and the forced drainage of the ground improved. As a result, the situation in which the groundwater in the surrounding ground B decreases can be avoided.

The form shown in FIG. 13 and FIG. 14 is predetermined outside the vertical supply path (vertical drain 101) between the vertical supply path (vertical drain 101) of the surrounding ground B and the improved ground A. FIG. The vertical drainage channels are formed by pouring a plurality of vertical drain materials 103a and 103b in a broken line at intervals. Horizontal drains 104a and 104b connected to the vacuum pumps 105a and 105b are connected to upper portions of the vertical drain materials 103a and 103b, and the upper portions of the vertical drain materials 103a and 103b and the vacuum pumps 105a and 105b. The upper surfaces of the horizontal drains 104a and 104b connected to) are covered with an airtight sheet 106.

Then, the water including the water replenishing material 102 is introduced into the vertical drain 101 constituting the vertical supply path and connected to the horizontal drains 104a and 104b connected to the upper portions of the vertical draining materials 103a and 103b. By operating the vacuum pumps 105a and 105b to be used, the water flows down the inside of the vertical drain 101, which is a vertical supply path, as indicated by the arrows in Fig. 13, and then exists in the intermediate layer or the lower layer of the surrounding ground B. The direction of the vertical drain material 103a constituting the vertical drainage path formed between the vertical supply path (vertical drain 101) and the improved ground A through the sand layer or organic soil layer C having high permeability; In the direction of the vertical drain material 103b constituting the vertical drainage channel formed on the outside of the vertical supply path (vertical drain 101) and passing through the vertical drain materials 103a and 103b constituting the vertical drainage path respectively. B) is discharged out.

The water repellent material 102 contained in the water includes the sand drain or organic soil layer C having high water permeability and the vertical drain material 103a and 103b constituting the vertical drainage path from the vertical drain material 101 constituting the vertical absorption path. Through the flow of water to the outside of the ground (B) through the flow, the vertical drain material 101 constituting the vertical supply passage flows down, diffuses in the highly permeable sand layer or organic soil layer (C), the vertical drainage channel It leads to the vertical drain materials 103a and 103b which comprise.

A part of the water repellent material 102 stagnates in the sand layer or the organic soil layer C having high permeability, creates a partial blockage state in the sand layer or the organic soil layer C having high permeability, and the water permeability decreases. The water including the water repellent material 102 concentrates on the interlayer portion of the partially permeable sand layer or the organic soil layer C, and passes through the interlayer portion at a high speed. In this process, the gap portion is closed by the index member 102.

In this way, the interlayer portions in the sand layer or organic soil layer C having high permeability are sequentially closed by the water repellent material 102, and the sand layer or organic soil layer C having high permeability as shown in FIG. ), The exponent zones 107a and 107b made of the exponent material 102 absorbed and expanded are formed.

In this case, since the index zones 107a and 107b are widely formed in the sand layer or the organic soil layer C having high permeability between the improved ground A and the surrounding ground B, the sand layer and the organic soil layer C The groundwater channel flowing through) is more surely cut off.

15 and 16 show a form of forming a vertical drainage channel on the outside of the vertical supply path. In the embodiment shown in FIGS. 15 and 16, the vertical drainage path is formed by pouring a plurality of vertical drain materials 103 in a dashed line at predetermined intervals outside the vertical supply path (vertical drain 101).

As long as the vertical drain material 103 to be used can form a drainage path in the depth direction of the surrounding ground B, specifically, a long plastic net is used as the core material, and a nonwoven fabric, felt, What provided the filter layer which consists of fiber sheets, such as a woven fabric and a knitted fabric, is mentioned. In this case, it is preferable that the filter layer of the vertical drain material 103 is comprised by the fiber sheet which has the hole of the size where the water supply material 102 cannot permeate or is difficult. In addition, in addition to placing the vertical drain material 103, the vertical drainage pipes pipes (hole pipes) having a large number of holes (perforated pipes) having no holes or difficult to permeate in the surrounding ground (B), or the surrounding ground ( A columnar sand layer may be provided and formed in B).

Moreover, the horizontal drain material 104 connected to the vacuum pump 105 is connected to the upper end of the vertical drain material 103 which comprises a vertical drainage path, The upper surface is covered with the airtight sheet 106. As shown in FIG.

As shown in FIG. 15 and FIG. 16, the water including the water repellent material 102 is introduced into the vertical drain 101 constituting the vertical supply path and the vacuum pump 105 is operated to simultaneously operate the water. As shown by the arrow in FIG. 15, after flowing down the inside of the vertical drain 101 which is a vertical supply path, it flows through the highly permeable sand layer and organic soil layer C which exist in the intermediate | middle layer or lower layer of the surrounding ground B, In addition, through the vertical drain 11 constituting the vertical drainage channel formed in the improved ground A and the vertical drain material 103 constituting the vertical drainage path formed outside the vertical supply path (vertical drain 101). Drained out of the ground;

The water repellent material 102 contained in the water constitutes the vertical drainage channel formed in the sand layer, the organic soil layer C, and the improved ground A having high water permeability from the vertical drain material 101 constituting the above-mentioned vertical absorption path. Vertical drain material constituting the vertical supply passage through the vertical drain 11 and the vertical drain material 103 constituting the vertical drainage path, and the flow of water to the outside of the improved ground A and the surrounding ground B outside. (101) flows down, diffuses into the high permeability sand layer or the organic soil layer (C), and reaches the vertical drain materials 11 and 103 which comprise a vertical drainage path.

A part of the water repellent material 102 is stagnated in the sand layer or the organic soil layer C having high permeability, creates a partial blockage state in the sand layer or the organic soil layer C having high permeability, and the water flow rate decreases. The water including the water repellent material 102 concentrates on the interlayer portion (the portion where no blockage occurs) of the sand layer or the organic soil layer C having a partially blocked permeability, and passes through the interlayer portion at a high speed. In this process, the gap portion is closed by the index member 102.

In this way, the interlayer portions in the sand layer or organic soil layer C having high water permeability are sequentially closed by the water repellent material 102, and the sand layer or organic soil layer having high water permeability as shown in FIG. In C), an index zone 107 made of the index member 102 is formed.

By this water stop zone 107, the flow path of the groundwater which consists of highly permeable sand layers or organic soil layers (C) between the improved ground (A) and the surrounding ground (B) is cut off. The situation that the groundwater in the ground B is lowered can be avoided.

On the other hand, if the highly permeable sand layer or the organic soil layer (C) does not exist over the improved ground and the surrounding ground, or if the intermediate gravel layer (D) exists above the highly permeable sand layer or the organic soil layer (C), Even if water including the index member 102 passes through the intermediate gravel layer D, the index member 102 does not stay in the intermediate gravel layer D, but forms a vertical drainage path in the improved ground A through water flow as it is. It moves to the vertical drain material 11 which comprises the vertical drain material 11 and the vertical drain path in the surrounding ground B.

In the middle gravel layer D, the index material 102 that has moved in the middle gravel layer D in accordance with the water flow cannot pass through the index material 102 on the surfaces of the vertical drain materials 11 and 103 constituting the vertical drainage channel. Alternatively, it is blocked by a filter layer having a hole having a difficult size and cannot enter into the vertical drain materials 11 and 103, and adheres to the vertical drain 11 and 103 surfaces, thereby clogging the filter layer on the surface of the vertical drain 11. The index zone 107 is formed therein.

The index zone 107 formed in the filter layer on the surface of the vertical drain 103 has a vertical drain 11 on the side of the improved ground A, which improves the flow of groundwater in the intermediate gravel layer D across the improved ground A and the surrounding ground B. ) And the vertical drain material 103 on the side of the surrounding ground (B), and by this index zone 107, the intermediate gravel layer (D) over the improved ground (A) and the surrounding ground (B). The flow path of the groundwater is cut off, and the situation that the groundwater of the surrounding ground B falls with the forced drainage of the ground improvement can be avoided.

In addition, the example shown to the said embodiment is only a mere explanatory example, For example, according to the kind of improved ground peripheral part B, the composition line of a vertical drainage path is double, 3 around the improved ground peripheral part B. It can change freely within the range as described in the column of a claim, such as providing in the middle.

Claims (30)

In the soft ground improvement method of creating a decompression area | region isolated from the improved ground periphery using the vacuum pressure in the soft ground to improve, and draining the gap number in the said improved ground, the said improved ground into a hard ground. A vertical supply path is formed in the ground of the improved ground and / or the improved ground periphery, and water containing the index material is introduced into the vertical supply passage, and the ground is formed in the ground of the improved ground and / or the improved ground periphery through the vertical supply passage. The improvement method of the soft ground characterized by supplying water containing an index material. The method for improving soft ground according to claim 1, wherein the water containing the index component is a hydrophilic gel suspension. 3. The method for improving soft ground according to claim 2, wherein the hydrophilic gel is made of a polysaccharide salt. The method for improving soft ground according to claim 3, wherein the polysaccharide salt is a salt mainly containing CMC or sodium alginate. The softener according to claim 1, wherein the index material is one or two or more selected from coarse sawdust, wood flour, rice husk, grain flour, grain bran or husk, starch, clay, cement and super absorbent polymer. Improvement method of the ground. The method for improving soft ground according to claim 5, wherein the nutrient component of the microorganism is added to water containing the water repellent material. The method according to claim 1, wherein the index material is a coarse sawdust, wood flour, rice husk, grain flour, grain bran or shells, starch, clay, cement and one or more selected from the superabsorbent polymer microorganisms Improved construction method of soft ground, characterized in that the mixture. The method for improving the soft ground according to claim 1, wherein the water containing the water-containing material is supplied from the water-water tank storing water containing the water-containing material into the vertical supply passage through the supply pipe. 9. The water supply system of claim 8, wherein the floating check valve is disposed in the vertical feed passage, and in accordance with the excess supply of water including the feed material supplied through the supply pipe from the water tank, An improved construction method for soft ground, characterized in that the supply is cut off. The method of claim 1, wherein in the ground of the improved ground and / or the improved ground periphery, the vertical drainage material is formed by pouring a vertical drain material composed of a filter layer having a hole having a size that the surface is permeable through the index material. Improvement method of soft ground to do. The method for improving a soft ground according to claim 1, wherein in the ground of the improved ground and / or the improved ground periphery, a pipe having a plurality of holes through which the water repellant penetrates is piped in a depth direction to form a vertical supply path. The method for improving soft ground according to claim 1, wherein the water containing the water repellent material is gap water from the improved ground. 13. The method for improving a soft ground according to claim 12, wherein a groove or a pipe connected to the drain supply path of the gap water from the improved ground is connected to the upper end of the vertical supply passage. The method according to claim 12 or 13, wherein a layer of gravel or coarse sand is provided around the upper portion of the vertical drain material or pipe, and water containing the water repellent material is introduced into the layer of gravel or coarse sand. Improvement method of soft ground characterized by. In the improvement method of the soft ground which improves the said improved ground to a hard ground by creating the reduced pressure area | region isolated from the improved ground periphery using a vacuum pressure in the improved ground, and draining the pore number in the said improved ground, A vertical supply path is formed in the ground around the improved ground periphery, water containing the water repellent material is introduced into the vertical supply path, and between the vertical supply path and the improved ground and / or outside the vertical supply path. A method for improving a soft ground, comprising: forming a vertical drainage channel and draining water in the ground around the improved ground periphery through the vertical drainage channel. The method for improving soft ground according to claim 15, wherein a vertical supply path is formed in a broken line in the ground around the improved ground periphery. 16. The method for improving soft ground according to claim 15, wherein a vertical drainage path is formed between the vertical supply path and the improved ground in a broken line shape. 16. The method for improving soft ground according to claim 15, wherein the water containing the index component is a hydrophilic gel suspension. 19. The method for improving soft ground according to claim 18, wherein the hydrophilic gel is made of a polysaccharide salt. 20. The method for improving soft ground according to claim 19, wherein the polysaccharide salt is a salt mainly containing CMC or sodium alginate. 16. The method for improving soft ground according to claim 15, wherein the index material is one or two or more selected from coarse sawdust, wood flour, rice hull, grain flour, grain bran or shells, starch, clay, cement and super absorbent polymer. . 22. The method for improving soft ground according to claim 21, wherein the nutrient component of the microorganism is added to water containing the water repellent material. The method according to claim 15, characterized in that the index material is a mixture of microorganisms mixed with one or two or more selected from coarse sawdust, wood flour, rice hull, grain flour, grain bran or shells, starch, clay, cement and super absorbent polymer. Improvement method of soft ground to make. 16. The method for improving soft ground according to claim 15, wherein the water containing the water repellent material is supplied from the water repellent tank storing water contained in the water repellent material into the vertical supply passage through a supply pipe. 25. The water supply system of Claim 24, wherein the floating check valve is disposed in the vertical feed passage, and in accordance with the excess supply of water including the feed material supplied through the supply pipe from the still water tank, An improved construction method for soft ground, characterized in that the supply is cut off. 16. The method for improving a soft ground according to claim 15, wherein a vertical supply path is formed by pouring a vertical drain material composed of a filter layer having a hole having a size through which an index material is permeable. The method for improving a soft ground according to claim 15, wherein a vertical drainage channel is formed by pouring a vertical drain material composed of a filter layer having a hole whose size cannot penetrate or difficult to penetrate. The method for improving soft ground according to claim 15, wherein the water containing the water repellent material is gap water from the improved ground. 29. The method for improving a soft foundation according to claim 28, wherein a groove or a pipe connected to the drain supply path of the gap water from the improved ground is connected to an upper end of the vertical supply passage. 30. The method of claim 28 or 29, wherein a layer of gravel or coarse sand is provided around the upper portion of the vertical drain material, and water containing the water repellent material is introduced into the layer of gravel or coarse sand. Improvement method of soft ground to do.

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